Screens

Abstract

A screen assembly, such as a downhole/sand screen assembly, comprising first and second screen portions or screens longitudinally coupled together, wherein there is provided a fluid flow path between the first and second screen portions or screen. Optionally, the first and second sleeves are coupled or connected by a centralizer or further sleeve or screen, and/or optionally by or via first and second support ring.

What is claimed is: 
     
       1. A downhole screen, comprising a pipe and a plurality of ceramic discs stacked on each other around the pipe,
 wherein the pipe comprises a plurality of first ports, 
 wherein at least one spacer is provided between each two adjacent ones of the discs such that the adjacent discs are spaced from one another, and 
 wherein each of the at least one spacer is aligned with a respective one of the first ports of the plurality of first ports in the pipe and shaped to diffuse fluid flow exiting the respective first port in the pipe. 
 
     
     
       2. The downhole screen according to  claim 1 , wherein the first ports are circumferentially and/or axially spaced on the pipe. 
     
     
       3. The downhole screen according to  claim 2 , wherein portions of each disc have reduced internal diameter such that the pipe and the disc radially abut or contact one another at said portions so as to provide between said portions of the disc circumferential spaces between the pipe and the disc. 
     
     
       4. The downhole screen according to  claim 3 , wherein the circumferential spaces extend longitudinally between the adjacent discs. 
     
     
       5. The downhole screen according to  claim 3 , wherein the circumferential spaces are aligned with at least one of the first ports in the pipe. 
     
     
       6. The downhole screen according to  claim 3 , wherein a valve member is provided between a respective one of the first ports and a respective one of the circumferential spaces. 
     
     
       7. The downhole screen according to  claim 6 , wherein the valve member comprises a slidable member. 
     
     
       8. The downhole screen according to  claim 6 , wherein the valve member comprises at least one second port that is selectively alignable with or out of alignment with the respective first port of the pipe. 
     
     
       9. The downhole screen according to  claim 6 , wherein the valve member comprises at least one reed valve that is selectively alignable with or out of alignment with the respective first port of the pipe. 
     
     
       10. The downhole screen according to  claim 1 , comprising an inner sleeve slidable relative to the pipe. 
     
     
       11. The downhole screen according to  claim 1 , wherein the pipe comprises a base pipe or production tubing. 
     
     
       12. A downhole screen assembly comprising at least a first screen and a second screen, wherein the first screen is a downhole screen according to  claim 1 , and wherein at least one of:
 the first screen and second screen are longitudinally disposed relative to one another; 
 the first screen is selected to be provided in a high(er) flow area; 
 the second screen is selected to be provided in a low(er) flow area; 
 the second screen comprises wire having a cross-section comprising a triangular shape; and 
 the second screen comprises wire having a cross-section comprising a square shape. 
 
     
     
       13. The downhole screen according to  claim 1 , wherein the at least one spacer comprises first and second concave surfaces, the first and second concave surfaces facing in opposing directions and radially diverging. 
     
     
       14. The downhole screen according to  claim 1 , wherein the discs are annular. 
     
     
       15. The downhole screen according to  claim 14 , wherein the discs provide a filter media. 
     
     
       16. The downhole screen according to  claim 14 , wherein each of the at least one spacer is provided on a surface or face of a respective one of the discs of the plurality of discs. 
     
     
       17. The downhole screen according to  claim 1 , further comprising an outer sleeve around the plurality of ceramic discs, wherein the at least one spacer is shaped to diffuse fluid flowing through the respective first port from the pipe toward the outer sleeve. 
     
     
       18. The downhole screen according to  claim 1 , comprising an inner sleeve, wherein an outer surface of the inner sleeve abuts or contacts an inner surface of the pipe. 
     
     
       19. The downhole screen according to  claim 1 , comprising an inner sleeve, wherein the inner sleeve comprises at least one second port or reed valve which is selectively alignable with or out of alignment with at least one of the first ports of the pipe.